Nutritional studies: Often overly sensationalised – lead to confusing, conflicting messages in the end

Zayani Bhatt, 08 Sep 2017

You are what you read: To report research findings on studies, in regards to diet and nutrition, accurately, would influence individuals’ choices about what to eat and drink.

With the abundance of news articles available on the Internet every day, only those that share novel content become much-read and popular. This obsession with novelty is called neophiliac. And while not a problem in itself – supposedly to be associated with good health – it appears to be a problem in science news, particularly in news about nutrition.

The demand for novelty means news agencies are often forced to focus on or create narratives that upend conventional wisdom. This means even if new research does not suggest a new discovery about eating habits – ‘headlines’ at least will spin it as though it does.

It is therefore, very common to find headlines that one day depict fats are good for you; and a few weeks down the road say they are bad for you. In both instances, though, readers deem them as equally valid making it seem like the scientific community is constantly contradicting itself. This is however, not the case.

A healthy, balanced diet has never been conceptually complicated

The main barriers to a healthy, balanced diet are money, time and access – not scientific findings. In fact, a huge, global study published just last week in The Lancet, proved just this. Yet, headlines around the world said that the study changed previously believed ideas on the amount of fat and carbohydrate consumption needed for a healthy diet.

The study, which was conducted by researchers at the Population Health Research Institute in the McMaster University in Canada, followed 135,335 individuals from North America, Europe, South America, the Middle East, South Asia, China, Southeast Asia and Africa, over seven years. Led by Mahshid Dehghan, the study, known as the Prospective Urban Rural Epidemiology study, (PURE), used food frequency questionnaires.

The diets of the participants, aged between 35 and 70 were measured against the number of cardiovascular diseases and deaths from any cause. There were 5,796 deaths and 4,784 major heart attacks, strokes and other cardiovascular complications over the study period. The result of the study was that the healthiest people had diets that were full of fruits, beans, seeds, vegetables, fats and grains, and were low in refined carbohydrates and sugar.

Dehghan further advised that limiting fat consumption did not improve overall health. Instead, those with a diet exceeding 60% of carbohydrate consumption would do well to reduce this and increase fat consumption. Researchers found that the risk of death of those with the highest consumption of carbohydrates compared with those with the lowest, was 28%.

Comparatively, a high fat intake reduced the risk of death by 23%. This was true for all types of fat. The study also showed that an increase in bad, low-density lipoprotein from fat consumption was neutralised by a simultaneous increase in good, high-density lipoprotein.

Yet none of this upends conventional wisdom

“A diet full of fruits and vegetables and low in carbohydrates and sugars is healthy” may seem to be all too familiar, to almost anyone. Neither is the belief that replacing saturated fatty acids with carbohydrates and unsaturated fats will lower cholesterol – and subsequently the chances of heart attacks, strokes and premature death. Numerous studies over the past 50 years have shown this. Nonetheless, headlines for articles about this study have touted it as revelatory and new – something that upended what the scientific community currently believes.

There are several problems with this. Firstly, although Dehghan says she hopes the study will provoke low and middle-income countries to “refocus their attention toward reducing carbohydrate intake, instead of focusing on reducing fats” – she is ignoring the fact that in such countries, particularly Asian ones, people eat high carbohydrate and low fat diets because of lack of access, not personal choice.

Secondly, the confusion caused by the drive for novelty means even some doctors believe the scientific community is uncertain. For example, last year, the chair of cardiology at Cleveland Clinic, in the US, Steven Nissen, said there was a “nearly complete absence of high-quality randomised, controlled clinical trials studying meaningful clinical outcomes for dietary interventions” – and that this “has left dietary advice to cult-like advocates, often with opposite recommendations. One group advises virtually complete elimination of carbohydrates from the diet, whereas others promote a virtually fat-free diet.”

However, such trials for diet are impossible as it is difficult to keep the subjects unaware – perception of diet affects behaviour. Although in an effort to eliminate bias, PURE took blood samples to measure lipid content.

While one result in the study was relatively new – raw vegetables are healthier than cooked ones, and more fruits, seeds and beans are better than more vegetables – continually pretending that conventional wisdom has been completely upended, tempts readers to lose faith in science’s ability to discern the truth. MIMS